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| Last Updated:19/03/2014

Latest News(Archive)

Latest News

Bill Gates Backs Solar Powered Biochar Toilets, 18 March 2014/


Scientists in Colorado have developed a solar powered waterless toilets courtesy of financial backing from the storied founder of computing giant Microsoft.

The waterless solar powered toilet was developed by scientists from the University of Colorado with the backing of a generous grant from the Bill and Melinda Gates Foundation, and promises to revolutionise sanitation in poorer regions of the world which suffer from acute water shortages.


The toilet uses the power of the sun to raise the temperature of the human waste it contains to levels high enough to achieve sterilisation. A set of eight mirrors focus sunlight onto a tiny centimetre-wide square, where a rope of fiber optical cables then transfer the energy and use it to heat a reaction chamber to temperatures in excess of 300 degrees Celsius.


In addition to radically enhancing hygiene and reducing the likelihood of disease transmission caused by poor sanitation, the toilet can also make a major contribution to the environment and local agriculture, by transforming human waste into a type of charcoal fertiliser.


The heating process which sanitises the toilet’s contents also serves to dry it out and convert it into biochar – a charcoal which is capable of sequestering large amounts of carbon as well as enhancing soil fertility.


Karl Linden, Helen and Huber Croft Professor of Environmental Engineering at the University of Colorado and principal investigator of the project, said that this means the toilet can transform human waste into a valuable material, which is capable of improving agriculture by increasing water retention and soil stability.


According to Linden soil which consists of just 10 per cent biochar is capable of holding up to 50 per cent more water, and increasing the availability of plant nutrients.


Biochar can also be employed as a fuel, generating energy volumes comparable to commercial charcoal.


The University of Colorado undertook the project in response to the “Reinvent the Toilet Challenge” launched by the Gates Foundation, which seek to develop sanitation facilities which are capable of sanitising human effluent as well as recycling it into useful products.


Linden’s team won a grant of nearly $780,000 from the Gates Foundation for its solar powered toilet in August 2012, as well as another million dollars following the promise shown by their initial efforts.


Their toilet is one of 16 projects around the world which have enjoyed the backing of the “Reinvent the Toilet Challenge” since 2011.